Programming MC1321x from Linux

I'd like to be able to program the flash on a MC1321x Zigbee board from a linux host. Ideally using the embedded boot loader or using the P&E USB Multilink. I have .s19 files, I just want to load them without having to go find an MS-Windows machine every time.

Is there a linux version of the embedded bootloader app?

Is there a doc anywhere that has the 'on-the-wire' protocol for the embedded bootloader so I can write an app?